The invention relates to a cutter arrangement for automatically trimming of flat products, such as leaflets, magazines and books, wherein the arrangement includes one or more up and down movable knives, a clamping bar and a fixedly installed counter-knife associated with each cutting knife, and comprising a transporting device for the continued transport of the leaflets, magazines and books.
Cutters of this type have long been known and have generally proven effective in practical operations. The operating principle for such cutters is disclosed in the applicant's prior 1959 Swiss Patent No. CH-A-34 04 79. The cutter disclosed therein comprises an up and down movable cutting unit with three knives distributed over two cutting stations arranged one after another with respect to the movement direction of the leaflets, such that a frontal cut can be executed with one knife and that top and bottom cuts can respectively be executed with the other two knives. The cutting unit, the transporting device and movable end stops are connected to a joint drive mechanism. Despite modifications to individual parts of this cutter, the basic design has to date remained unchanged. Such cutters are also referred to as trimmers or automatic three side trimmers. They permit an automatic trimming even of thick paper products with a capacity of, for example, six copies per second. The cut performed by the knives is also called a scissoring cut and is executed in that the cutting knife moves above the cutting edge of the counter-knife. One advantage of this type of cut is the long service life of the knives, which is considerably longer when compared to a cutting with the aid of cutting strips. However, an exact knife guidance is required. In addition, two stations are absolutely necessary for trimming products on three sides.
With the aforementioned cutter, the force flow is comparably unfavorable and deformations cannot be avoided. The control movements are furthermore complicated and only a comparably light press-down force is possible. Finally, accessibility is limited and lubrication is very involved.